DESCRIPTION: Oral leukoplakia is a common clinical finding with a high rate of malignant transformation. Its accumulative features strongly support the rationale for its prevention before invasive lesions can grow. Oral cancer chemoprevention is very promising strategy. Nevertheless, current approaches are very far from being satisfactory because of their significant toxicity. Anti-angiogenesis has been known as one of cornerstones for cancer prevention. Our previous studies have indicated the effectiveness for tumor inhibition of laser selective microvascular targeting (MVT) with a 585 pulsed dye laser (PDL). There was also a significantly synergic effect found between the PDL and some chemopreventive agents. In this proposed study by using check pouch of a hamster model, we will determine 1) if we can further optimize laser parameters for highly-selective MVT treatment for oral mucosa; 2) if Celecoxib, a newly developed less toxic inhibitor of cyclooxygenase (COX)-2, will is safe and effective in treatment of oral leukoplakia; and 3) if there is a synergic effect when combined Celecoxib with PDL, to allow further reduction of potential side-effect with Celecoxib, without sacrificing its treatment efficacy. This is the first study in using a MVT technique for treatment of oral leukoplakia and in combining MVT with Celecoxib for oral cancer chemoprevention. This combined strategy of Celecoxib and PDL, if success in this proposed study, will provide a new and ideal way, called "photo-chemoprevention", for treatment of oral leukoplakia. This new therapy will be more efficacious and less toxic, and is safe and convenient enough to permit an out-patient treatment. The same concept and approach also is available for skin or other pre-malignant lesion located on tissue surface. [unreadable] [unreadable]